Bronson



March 3, 1964 o so 3,123,829

- SELF-LEVELING DEVICE Filed Aug. 16, 1960 3 Sheets-Sheet 1 FIG. I

iii i. 10% 6 ()1 U U IN V EN TOR.

ATTORNEY March 3, 1964 l. BRONSON SELF-LEVELING DEVICE Filed Aug. 16, 1960 3 Sheets-Sheet 3 INVENTOR. few/v5 flea/mm ATTOEA/EY United States Patent 3,123,829 SELF-LEVELING DEVICE Irving Bronson, Brooklyn, N.Y., assignor, by mesne assignments, to American Machine & Foundry Company, New York, N.Y., a corporation of New Jersey Filed Aug. 16, 1960, Ser. No. 49,857 Claims. (Cl. 108-436) This invention relates to a self-leveling device for receiving, storing and dispensing articles.

The subject matter of this application is related to my copending applications Serial No. 49,856 and Serial No. 49,912, both filed simultaneously herewith.

Under many circumstances, it is desirable to dispose a series of articles in stacked relation upon a wheelmounted carrier and to remove said articles therefrom as desired. Thus, for example, restaurants or similar food service institutions may require that a series of dish racks be stacked as they are removed from a dishwashing machine and thereafter transported to another locationat which the racks are unloaded as required. In this, as well as in many other applications, it is quite important that the loading and unloading points be maintained at a constant level regardless of the number of stacked articles disposed upon the carrier in order to minimize the amount of effort required and to maintain the uppermost rack or article at the most desirable level. Although selfleveling devices of this character have been suggested, they have been characterized by shortcomings which are overcome by the instant invention.

It is therefore an object of this invention to provide a self-leveling device for receiving, storing and dispensing articles which is simple in arrangement and construction and which effectively maintains a plurality of articles in stacked relation, with the uppermost article being maintained at a predetermined level regardless of the number of articles comprising the stack.

Another object of this invention is to provide a selfleveling device of the character indicated which may be readily adjusted to accommodate various stacks of articles as when it is desired to change over from a stack comprised of articles of a certain weight and vertical dimension to a stack comprised of articles of a different unit weight and vertical dimension.

It is also an object of this invention to provide a device of the character indicated wherein it is not necessary to employ special types of spring elements in order to provide for the maintenance of a stack of articles at a predetermined constant level regardless of the number of articles comprising the stack and variations in the characteristics of the group.

An additional object of this invention is to provide an arrangement wherein a stack elevating spring arrangement is employed which provides for varying the leverage exerted upon the spring means to accord with the degree v of winding or unwinding thereof. It is a further object to provide means for. adjusting the initial spring tension and degree of leverage exerted thereon.

This invention also has for its object the provision of a device of the character indicated wherein positioning means are provided for accurately locating the uppermost article of the stack at a predetermined elevation.

Other and further objects of this invention will become apparent from the description thereof contained in the annexed specification, or will otherwise become obvious. It will be understood that the invention here disclosed may be employed for other purposes to which the structure and arrangement are adapted.

In the accompanying drawings:

FIGURE 1 is a side elevational view of a self-leveling device embodying the features of the instant invention,

partly in section and also showing the carrier platform under load in broken lines;

FIGURE 2 is a top plan view of the device, portions of the carrier platform being broken away for purposes of clarity of illustration;

FIGURE 2a is a fragmentary view showing one of the cable reels;

FIGURE 3 is a cross-sectional view of the spring drum assembly taken along line 3-3 of FIGURE 2;

FIGURE 4 is a sectional View of FIGURE 3 taken along line 44 thereof showing the spring tension adjustment arrangement;

FIGURE 5 is an enlarged fragmentary view of the carrier platform carriage partly broken away;

FIGURE 6 is a sectional view of FIGURE 5 taken along line 66 thereof;

FIGURE 7 is a fragmentary front elevational view, partly in section showing one of the pillow blocks for .the biasing drum shaft; and

FIGURE 8 is a sectional view taken along line 8-8 of FIGURE 6.

A self-leveling, receiving, storing and dispensing device embodying the features of the instant invention is illustrated in FIGURES -1 and 2 of the accompanying drawings. As may be seen from said figures, the device comprises a wheel-mounted base assembly, designated generally by the numeral 10 which supports an upright firame assembly, designated generally by the numeral 11. A carrier assembly, designated generally by the numeral 12, receives, stores and dispenses the desired articles and is mounted for vertical movement on the upright frame assembly 11. Articles, such as dish racks for example, are stacked upon the carrier platform 12:: of the carrier assembly and with the placement of each successive rack thereon, the stack is depressed or lowered so that the uppermost article in the stack is always at the same working level. Conversely, as each article is successi-vely removed from the stack, the entire remaining stack is elevated so that the next succeeding article is brought up to the desired working level.

The base assembly '10 in the form of the invention illustrated comprises a generally rectangular frame 13 which is advantageously formed of angle members of steel, aluminum or other suitable material. The frame is further reinforced by horizontal bars. 14 which also serve as securing means for the mounting plates 16 of the casters 15, which are mounted adjacent the corners of the base. By forming the base in the manner indicated, it is possible to make use of this portion of the device for further storage of used racks for example. Thus, as a new rack is removed from the stack upon the carrier platform which is elevated as a consequence of such removal, a used rack may be disposed upon the frame assembly in the space thus formed.

The upright frame assembly 11 is mounted upon the wheeled base It and comprises a pair of vertical trackways 17 and 18, disposed on the opposing sides of the base frame 13. The trackways are of similar construction and the same reference numerals will be used to identify similar parts. Each of trackways 17 and 18 comprises a pair of spaced-apart guide rails 19 and 20, each having a flange portion 21 and a head portion 22. As will be more particularly seen from FIGURE 5, the rail heads 22 are advantageously provided with a plurality of vertically spaced arcuate indentations 23 which serve as positioning detents for the carriage rollers, as will be more particularly apparent hereafter. Furthermore, it should be noted that the rail heads 22 may be formed independently of the flange portions 21 and remcvably secured thereto as by screws or bolts, so that the rail heads 22 may be removed and replaced as required due to wear or for the purpose of substituting a rail head having differently spaced indentations. Inclined brace members 24 and 25 extend from the base to the upper extremity of the guide rails. The upper ends of each pair of guide rails and the associated inclined brace member are secured between a pair of horizontally disposed rearwardly extending bracket plates 26 and 26a.

These bracket plates serve to support an important feature of this invention which resides in an ingenious means for presetting a spring drum so as to provide a predetermined resistance to variation in the level of the carrier platform 12a.

Thus, as may be seen by reference to FIGURES 1 to 4, the rearward ends of the bracket plates 26 are rigidly secured, as by welding 27, to a transverse hollow spring drum 28. At each end of this drum, there is housed a ball bearing 29 which rotatably secures a shaft 36. Intermediate of said bearings 29 are provided a pair of flanged collars, generally designated by the numerals 3]., 32, the bodies 33 of said collars 31, 32 being formed with grooves 34 to receive a coiled torsion spring 35. One of the collars 31 is secured to the shaft by a radially disposed pin 3s; and the other of said collars 32 is rotatable with respect to the shaft 30. The ends of the aforesaid coiled torsion spring 35 are also aflixed to the collars so that any rotation of the collar 32 with respect to the shaft 30 imparts a set or corresponding resistance of the spring to any opposing torque which may be exerted upon the shaft 30.

The rotation of the collar 32 with respect to the shaft 30 may be accomplished by means of a detent or pin 37 which is removably receivable within a plurality of equally spaced-apart radial apertures 38 formed in the flanged portion 326: of said collar 32, the said detent or pin 37 being provided with an expanded annular portion 39 which is seatable upon annular shoulders 40 formed in each of said radial apertures 38. The said pin 37 is also slidably received in a slot 41 formed in the hollow drum 23.

It will be noted from the foregoing arrangement that the coiled torsion spring 35 may be rotated with respect to the shaft 39 by simply rotating the detent or pin 37 in the direction of the arrow shown in FIGURE 4 so that said pin will be displaced from an initial position at one end of the slot 41 to the other end thereof, at which location the pin will occupy the position shown in dotted lines in said FIGURE 4 and designated therein by the numeral 37a. Upon such rotation, another of the said radial apertures 38 is aligned with that end of the slot which was occupied by the detent or pin 37 prior to its aforesaid rotation. To maintain this position, another of said pins 37 may be inserted in said last-mentioned aperture so as to be biased against the edge of the slot by the force of the torsion spring. Further rotation of the collar 32 with respect to the shaft 39 may also be accomplished in a similar manner so as to align successively any of the apertures 38 with the ends of the slot 41 and produce any desired amount of torsion in the spring 35.

The shaft is maintained between the bearings 29 by a pair of opposing screws 42. These screws 42 are axially received in opposite ends of the shaft, said ends projecting from within the hollow drum into bores 43 formed within a pair of hollow conical reels 44 rotatable together with the shaft. The reels are secured to the ends of the shaft by washers aifixed to the shaft by the aforesaid screws 42 and over-lapping the ends of the shaft so as to abut against annular shoulders 46 formed within said bores 43. Each end of the shaft 30 is provided with a transverse pin 47 which is locked within radial depressions 47a formed in the inner faces of the reels 44.

The external periphery of each of the reels 44 is provided with a helical groove 49 which receives a flexible member, such as a flexible cable 50 which also extends radially into an aperture 51 formed within each of said reels, in which position the cable St) is maintained by a set screw 52. The reels are also rotatable with respect 4 to the bracket plates 26 and 26a, said plates being maintained in a spaced relation by suitable fastening elements 53.

t will be seen from this arrangement that the coiled spring 35 may be initially deflected to any desired extent by rotation of the detent or pin 37. Such deflection together with the corresponding counter-pull of the flexible cables will vary the lifting force applied to the carrier platform to accommodate items of different weights.

The aforesaid cable is connected to a carriage assembly, generally designated by the numeral 54, in a manner hereinafter described, so as to support the carrier assembly 12. Thus, for any given weight placed upon the platform of the carrier assembly, there will be a corresponding deflection of the flexible cable, the amount of such deflection being determined by the aforesaid moment arm of the cable with respect to the axis of the reel and the preset torsion of the coiled spring 35. In this connection, it will be particularly noted that the moment arm of the cable will lengthen as the carrier platform descends and the counter-pull of the spring increases; and the moment arm will shorten as the carrier platform rises and the counterpull of the spring decreases.

FIGURES 1-8 illustrate the arrangement of the carriage assembly as supported by the flexible cable. Thus, it will be seen from these figures that the flexible cable received within the helical groove of each of the reels extends horizontally, as at 50a, into contact with the external periphery of an idler puller 55 rotatably mounted, as by a shaft and nut assembly 55a between each of the bracket plates 26 and 26a. From said idler pulley the flexible cable extends substantially vertically, as at 5%, in the direction of the carriage assembly to the external periphery of a biasing drum 56 forming part of said carriage assembly and rotatably secured, as by a shaft 57, upon a rectangular carriage plate 58 mounted upon the carrier assembly 12 by bolts 59 and disposed to move vertically between the guide rails 19 and 20, as for example, to the position depicted in broken lines in FIGURE 1 and designated by the numeral 53a, said vertical movement corresponding to the vertical movement of the carrier assembly 12.

The flexible cable is disposed within a radial aperture 60 formed within the biasing drum, said cable being secured therein by a suitable screw 61 or other fastening element. The biasing drum itself is mounted upon the shaft 57, as by a pin 62, the axis of said shaft 57 being disposed equidistantly from the sides of the carriage plates 58. In the upper and lower portions of each of the carriage plates 58, a pair of carriage rollers 63, 64 is mounted, each of said rollers being grooved and provided with flanged portions 65 and cylindrical body portions 66. The axes of the rollers 63 and 64 are aligned on opposite sides of a vertical axis of the carriage plate and consequently are contactable with the opposing rail heads of the trackway. It should be noted that the space between the rail heads exceeds the diameter of the cylindrical body portions of the carriage rollers. As a consequence of this arrangement, the entire carriage assembly is canted or inclined so that the upper roller 63 bears against the forward rail head and the lower roller 64 bears against the rearward rail head, as may be more particularly seen from FIGURES 1 and 5. This inclination is maintained by the counter-clockwise couple produced by the upward tension of the flexible cable at 50b and the downwardly directed weight of the carrier assembly and any articles disposed thereon. An imbalance in the weight of the carriage in the forward direction similarly causes this inclination.

The rollers are mounted upon ball bearings 67 secured to the carriage plate by bolt and nut assemblies 68, the ball bearings being spaced from the carriage plate by suitable washers 69, whereby rotation of said rollers is permitted.

The arcuate indentations 23 serve as positioning detents for the rollers. Thus, when the carriage assembly has been lowered by a weight imposed upon the carriage platform to a position wherein said rollers are in the approximate vicinity of the centers of said arcuate indentationsi.e., where the rollers make contact with any portion of said indentations, the rollers tend to be forced to the center of said indentations by the canting action described above. In this way, the level of the carriage assembly, and hence of the carrier platform, will tend to be definitely determined at positions corresponding with the arcuate indentations.

The biasing drum may be rotated to adjust the initial position of the cable on the conical reel and thereby adjust its moment arm with respect to the axis of the coiled spring. This rotation may be accomplished by rotating the transverse shaft 57, said shaft being secured as aforesaid to each biasing drum and also being provided with an aperture 70 wherein a suitable rod or lever (not shown) may be inserted for the purpose of manually rotating the shaft in either of the directions of the arcuate arrows depicted in FIGURE 6 of the drawings.

To prevent overwinding of the biasing drum, the shaft is provided with a pair of sleeves 71 secured against rotation with respect to the shaft by transverse pins 72 extending through the shaft and received in slotted portions 71a of said sleeves. The external peripheries of said sleeves are provided with threads 73 and engaged with the internally threaded portions of a pair of pillow blocks 74 secured by bolts 75 to a flanged portion 76 of the carrier platform, said carrier platform comprising a generally rectangular frame composed of angle members of steel or other suitable material bolted together as at 77. It will be noted that the sleeves 71 are slidable upon the shaft in an axial direction, the limits of such slidable movement being the abutment of the pins 72 with the inner ends 71b of the slots and the abutment of the sleeves with the carriage plate. Between such limits, the cable may be wound upon the biasing drum without risk of overwinding in either direction.

With this arrangement, the carrier platform may receive a plurality of articles of equal weights, such as dish racks, the uppermost of said racks being maintained at a predetermined level. When the stacks are composed of a different weight, the level thereof may be adjusted by appropriate setting of the spring drum and of the biasing drum. It will be seen that such adjustment is easily, quickly and conveniently accomplished, and does not require the employment of specialized spring elements, the soiled torsion spring within the spring drum being of conventional design. Moreover, a definite positioning of the carrier platform is accomplished Without the necessity of using a delicate or unduly complex mechanism. Furthermore, as pointed out above, the adjustment of the biasing drum permits adjustment of the initial moment arm, and hence of the initial moment exerted upon the coiled spring, thereby allowing the user to compensate for any variation of the spring rate thereof.

The embodiment of the invention illustrated and described hereinabove has been selected for the purpose of clearly setting forth the principles involved. It will be apparent, however, that the present invention is susceptible to being modified in respect to details of construction, combination and arrangement of parts which may be resorted to without departure from the spirit and scope of the invention as claimed.

I claim:

1. An improved self-leveling device comprising in combination a base member supporting an upright frame, a vertically movable carriage retained within said frame, said carriage supporting a platform adapted for receipt of a plurality of articles, said carriage being supported by at least one flexible cable communicating with reel means afi'ixed to a rotatable shaft which is retained against axial movement, said shaft being biased by a coiled torsion spring disposed thereon, said shaft being provided with means for imparting an initial deflection to said coiled torsion spring, said reel means having means to vary the leverage exerted upon said spring, said reel means comprising a conical member, the external periphery of said conical member being formed with a helical groove, the said flexible cable being received within said groove, the said carriage including biasing means communicating with the flexible cable, the said biasing means being adjustable to vary the position of the flexible cable within said groove, whereby the topmost portions of said articles are maintained at a constant level independently of the number of such articles.

2. A device according to claim 1, said reel means comprising a conical member, the external periphery of said conical member being formed with a helical groove, the said flexible cable being wound upon said groove, the said carriage including a biasing drum secured to the flexible cable, said biasing drum being supported upon a rotatably adjustable shaft, said flexible cable being windable upon said biasing drum upon rotational adjustment of the shaft, whereby the initial point of engagement between said flexible cable and said conical member is varied.

3. An improved self-leveling device comprising in combination a base member including a generally rectangular frame provided with a plurality of casters, said base members supporting a pair of upright trackways disposed upon opposing sides of said base member, each of said trackways including a pair of spaced-apart guide rails, the said guide rails each having a flange portion and a head portion, the said head portion being provided with a plurality of equally spaced-apart arcuate indentations, a pair of vertically movable rectangular plates disposed between said guide rails and supporting a generally rectangular platform adapted for receipt of a plurality of racks of equal weights, the said rectangular plates being provided with a pair of cylindrical drums mounted upon a shaft extending through said rectangular plates, a pair of flexible cables secured within and wound upon the said cylindrical drums, said flexible cables extending in a substantially vertical direction to the external peripheries of a pair of idler pulleys, the substantially vertical position of said flexible cables being offset with respect to the central vertical axes of said rectangular plates, whereby said plates are inclined with respect to said guide rails, each of the said rectangular plates being provided with a pair of rollers rotatably disposed upon ball bearings secured upon said shaft, the upper of said pair of rollers being contactable with the head portion and arcuate indentations of one of said guide rails, the lower of said rollers being contactable with the head portion and arcuate indentations of the other of said guide rails, each of the said idler pulleys being mounted between a pair of opposing horizontal brackets affixed to the opposing pairs of guide rails, said pair of brackets also supporting a rotatable tubular drum which receives a shaft coaxial with said drum, said coaxial shaft being mounted within a pair of ball bearings secured at opposing ends of the tubular drum, said shaft also being provided with a pair of flanged collars upon which is seated a coiled torsion spring, one of said collars being afiixed by pin means to said coaxial shaft, the other of said collars being rotatably secured to said shaft and provided with a plurality of radial apertures, the said apertures being engageable with a removable radial pin abuttable against the ends of a slot formed in the tubular drum, said last-mentioned collar being rotatable by said pin to impart a predetermined deflection to said torsion spring, said spring being securable in the position of such deflection by the abutment of another of said radial pins against one end of the said slot, each end of said coaxial shaft being provided with a hollow conical reel received between each pair of said opposing brackets, each of said reels having an external periphery provided with a helical groove, the said flexible cables extending from said idler pulleys to said helical groove and secured within said conical reels, the initial point of contact between said flexible cables and said conical reels being determined by the amount of said predetermined deflection of the torsion spring and the rotational displacement of said cylindrical drums upon said rectangular plates, whereby the initial moment exerted by said cables upon said torsion spring is determined, the shaft connecting said cylindrical drums being provided with a pair of sleeves threadedly engageable with the bores of a pair of pillow blocks secured to said platform, said pillow blocks having threads of opposite hands, said sleeves being provided with slotted portions wherein is received a pair of transverse pins extending through said last-mentioned shafts, said transverse pins being abuttable against the ends of said slots upon rotation of said shaft, said shaft being provided with a transverse aperture for reception of suitable rotating means, said cable being wound upon said cylindrical drums upon rotation of said shaft to the extent permitted by said sleeves.

4. An improved self-leveling device comprising in combination a base member supporting an upright frame, a vertically movable carriage retained within said frame, said carriage supporting a platform adapted for receipt of a plurality of articles, said carriage being supported by at least one flexible cable communicating with reel means affixed to a rotatable shaft, said shaft being biased by a coiled torsion spring disposed thereon, said shaft being provided with means for imparting an initial deflection to said coiled torsion spring, whereby the topmost portions of said articles are maintained at a constant level independently of the number of such articles, said reel means having means to vary the leverage exerted upon said spring, said reel means comprising a conical member, the external periphery of said conical member being formed with a helical groove, the said flexible cable being wound upon said groove, the said carriage including a biasing drum secured to the flexible cable, said biasing drum being supported upon a rotatably adjustable shaft, said flexible cable being windable upon said biasing drum upon rotational adjustment of the shaft, whereby the initial point of engagement between said flexible cable and said conical drum is varied, the rotational adjustment of said biasing drum being limited by stop means mounted concentrically upon the shaft of said biasing drum.

5. An improved self-leveling device comprising in combination a base member supporting an upright frame, a vertically movable carriage retained within said frame, said carriage supporting a platform adapted for receipt of a plurality of articles, said carriage being supported by at least one flexible cable communicating with reel means affixed to a rotatable shaft, said shaft being biased by a coiled torsion spring disposed thereon, said shaft being provided with means for imparting an initial deflection to said coiled torsion spring, whereby the topmost portions of said articles are maintained at a constant level independently of the number of such articles, said reel means having means to vary the leverage exerted upon said spring, said reel means comprising a conical memher, the external periphery of said conical member being formed with a helical groove, the said flexible cable being wound upon said groove, the said carriage including a biasing drum secured to the flexible cable, said biasing drum being supported upon a rotatably adjustable shaft, said flexible cable being Windable upon said biasing drum upon rotational adjustment of the shaft, whereby the initial point of engagement between said flexible cable and said conical drum is varied, the rotational adjustment of said biasing drum being limited by stop means associated with said shaft, said shaft being provided with at least one sleeve, the external periphery of said sleeve being threadedly engaged with a pillow block secured to said platform, said sleeve being axially displaceable upon rotation of the shaft, said sleeve being provided with a slotted portion abuttable with a pin provided in said shaft, whereby the axial displacement of said sleeve is limited.

References Cited in the file of this patent UNITED STATES PATENTS Simpson July 12, 1960 

1. AN IMPROVED SELF-LEVELING DEVICE COMPRISING IN COMBINATION A BASE MEMBER SUPPORTING AN UPRIGHT FRAME, A VERTICALLY MOVABLE CARRIAGE RETAINED WITHIN SAID FRAME, SAID CARRIAGE SUPPORTING A PLATFORM ADAPTED FOR RECEIPT OF A PLURALITY OF ARTICLES, SAID CARRIAGE BEING SUPPORTED BY AT LEAST ONE FLEXIBLE CABLE COMMUNICATING WITH REEL MEANS AFFIXED TO A ROTATABLE SHAFT WHICH IS RETAINED AGAINST AXIAL MOVEMENT, SAID SHAFT BEING BIASED BY A COILED TORSION SPRING DISPOSED THEREON, SAID SHAFT BEING PROVIDED WITH MEANS FOR IMPARTING AN INITIAL DEFLECTION TO SAID COILED TORSION SPRING, SAID REEL MEANS HAVING MEANS TO VARY THE LEVERAGE EXERTED UPON SAID SPRING, SAID REEL MEANS COMPRISING A CONICAL MEMBER, THE EXTERNAL PERIPHERY OF SAID CONICAL MEMBER BEING FORMED WITH A HELICAL GROOVE, THE SAID FLEXIBLE CABLE BEING RECEIVED WITHIN SAID GROOVE, THE SAID CARRIAGE INCLUDING BIASING MEANS COMMUNICATING WITH THE FLEXIBLE CABLE, THE SAID BIASING MEANS BEING ADJUSTABLE TO VARY THE POSITION OF THE FLEXIBLE CABLE WITHIN SAID GROOVE, WHEREBY THE TOPMOST PORTIONS OF SAID ARTICLES ARE MAINTAINED AT A CONSTANT LEVEL INDEPENDENTLY OF THE NUMBER OF SUCH ARTICLES. 